Bonsai Myths-- Water Droplet
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Mike Jones
Kev Bailey
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Bonsai Myths-- Water Droplet
I was going to seek your assistance in forever putting to bed the myth that water droplets on leaves can burn them. I decided to do a quick Google and look what I came up with - http://arago.elte.hu/files/WaterDropOnLeaf_NewPhytologist-Commentary-Jones.pdf
If anyone has anything to add, I'd appreciate it.
If anyone has anything to add, I'd appreciate it.
Last edited by Chris Cochrane on Wed Jun 16, 2010 12:31 am; edited 1 time in total (Reason for editing : title clarification)
Kev Bailey- Admin
Bonsai Myths
I thought the focal point of a water droplet had been proved to be way past the back of the leaf?
Guest- Guest
Re: Bonsai Myths-- Water Droplet
Kev
On another forum this subject came up recently and I was shot down in flames for suggesting that it does burn (not all species of course) and IMHO, overhead watering in the midday sun is just plain daft. I learnt by my mistakes of 25 years ago. I water in the evening since then, when the sun is down, everything is at peace, the birds are getting ready for their zzzz's, beer in hand and so on.
YES it does burn certain leaf types. I will not be swayed.
Mike
On another forum this subject came up recently and I was shot down in flames for suggesting that it does burn (not all species of course) and IMHO, overhead watering in the midday sun is just plain daft. I learnt by my mistakes of 25 years ago. I water in the evening since then, when the sun is down, everything is at peace, the birds are getting ready for their zzzz's, beer in hand and so on.
YES it does burn certain leaf types. I will not be swayed.
Mike
Mike Jones- Member
Re: Bonsai Myths-- Water Droplet
Sway or not, it is basic physics; there has to be some distance between the drop (lens) and the leaf (focal plane) and it would have to be a precise distance relative to the size and diameter of the drop in order to have the light focused into a pin-sized spot. Since the water is sitting on the leaf, there's no focal length. You can prove this by laying a magnifying glass on your hand in bright sunlight. Nothing happens. Lift the lens and focus the sunlight and . . . OUCH!
If your water has something in it that is left behind when the water evaporates (acid from acid rain???), it is conceivable that whatever that material is could do damage to the leaf. But that's it.
Andy Walsh, another old IBCer I've heard little of recently, gave us a detailed explanation of the physics behind this most hoary of horticultural myths way back in the early mailing-list days of the IBC. Alas, it was lost during one of my many computer change-overs. But this article does the job, too.
I had started an article on bonsai myths -- there are a LOT of them -- but a quick search here failed to find it. I'll keep looking.
If your water has something in it that is left behind when the water evaporates (acid from acid rain???), it is conceivable that whatever that material is could do damage to the leaf. But that's it.
Andy Walsh, another old IBCer I've heard little of recently, gave us a detailed explanation of the physics behind this most hoary of horticultural myths way back in the early mailing-list days of the IBC. Alas, it was lost during one of my many computer change-overs. But this article does the job, too.
I had started an article on bonsai myths -- there are a LOT of them -- but a quick search here failed to find it. I'll keep looking.
JimLewis- Member
Re: Bonsai Myths-- Water Droplet
If it was the case, all the trees and plants in my neighbourhood would be badly damaged: we've had several days of hot, weather with showers of rain, and even some hail storms (fortunately not big ones in my area) sometimes lasting just a few miniutes, and very sunny and hot spells in-between.
So far, they look perfectly healthy, including my tomato plants that haven't even developed signs of the dreaded fungal diseases that are so frequent on these plants.
Not to mention the "thermic shock": water from the hose is warmer than the rain from a storm.
But of course, it is more sensible to water your trees in the evening, if only because it evaporates less quickly. So it's cheaper, and more environment-friendly.
So far, they look perfectly healthy, including my tomato plants that haven't even developed signs of the dreaded fungal diseases that are so frequent on these plants.
Not to mention the "thermic shock": water from the hose is warmer than the rain from a storm.
But of course, it is more sensible to water your trees in the evening, if only because it evaporates less quickly. So it's cheaper, and more environment-friendly.
AlainK- Member
Re: Bonsai Myths-- Water Droplet
Thanks all. Jim's put into words exactly what I wanted to say and Alain's logic is unassailable.
About the only other detrimental effect I can understand is the trapping of airborne fungal spores in water and them drying onto the leaf surface, beginning a fungal attack. Is that what you were alluding to with the blight reference Alain?
About the only other detrimental effect I can understand is the trapping of airborne fungal spores in water and them drying onto the leaf surface, beginning a fungal attack. Is that what you were alluding to with the blight reference Alain?
Kev Bailey- Admin
Re: Bonsai Myths-- Water Droplet
AlainK wrote:If it was the case, all the trees and plants in my neighbourhood would be badly damaged: we've had several days of hot, weather with showers of rain, and even some hail storms (fortunately not big ones in my area) sometimes lasting just a few miniutes, and very sunny and hot spells in-between.
Exactly! If this myth where true then most of Florida would be a ravaged wasteland as it rains almost every afternoon preceded and followed by 90+ full sun days. I think anyone who has ever visited my neighborhood can attest, greenery is not an issue here.
Ed
EdMerc- Member
Re: Bonsai Myths-- Water Droplet
Kev Bailey wrote:
About the only other detrimental effect I can understand is the trapping of airborne fungal spores in water and them drying onto the leaf surface, beginning a fungal attack. Is that what you were alluding to with the blight reference Alain?
Er... Probably
I don't know really how it works, but two years ago, most tomato plants in gardens yielded very little crop due to diseases. The leaves are very sensitive to that, and that's the only reason it is strongly recommended to water the foot, not the leaves, whether it's in the evening, in the morning, or during the day. That's why everyone uses Bordeaux mixture, which is on the most efficient preventiive treatment. But that's a different story...
AlainK- Member
Re: Bonsai Myths-- Water Droplet
most of Florida would be a ravaged wasteland
Well, I spent 35 years in Florida's government working on environmental problems and that's not too far off base -- especially in the central and south parts.
JimLewis- Member
Re: Bonsai Myths-- Water Droplet
Mostly against me and all the people I worked with from Claude Kirk through Lawton Chiles. We worked hard, but it was largely fruitless, considering who really runs the state -- especially in the last 10 years or so when it has been pretty much "anything goes."
JimLewis- Member
Re: Bonsai Myths-- Water Droplet
JimLewis wrote:
I had started an article on bonsai myths -- there are a LOT of them -- but a quick search here failed to find it. I'll keep looking.
One of the best articles ever...
"Ten Great Bonsai Myths", Bonsai: Journal of the American Bonsai Society. Vol. 24, No. 1. Spring 1990 , p. 8-11. By Jerry Meislik
Check your library I bet its there...
http://www.bonsaihunk.us/Fallacies.html
Last edited by Rock on Tue Jun 15, 2010 7:33 pm; edited 1 time in total (Reason for editing : turrible spelling)
rock- Member
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